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Life-history evolution in uncertain environments: bet hedging in time
Henry M Wilbur1, Volker H W Rudolf
1Department of Biology, University of Virginia, Charlottesville, Virginia 22904, USA. hwilbur@virginia.edu
The American Naturalist
|September 2, 2006
Summary
Environmental uncertainty favors both developmental delay and iteroparity in species. These life-history adaptations help organisms survive and reproduce in unpredictable conditions, enhancing population resilience.
Area of Science:
- Ecology
- Evolutionary Biology
- Life History Theory
Background:
- Many species exhibit variable age at maturity and iteroparity as adaptations to environmental uncertainty.
- These life-history traits are crucial for species survival and reproduction in unpredictable ecosystems.
Purpose of the Study:
- To analyze a stochastic model combining developmental delay and iteroparity with density-dependent fertility.
- To investigate how environmental uncertainty influences the selection of these life-history adaptations.
Main Methods:
- Stochastic modeling approach.
- Analysis of a model incorporating variable age at maturity (developmental delay) and repeated reproduction (iteroparity).
- Invasion analysis to assess selective pressures.
Main Results:
- Environmental uncertainty favors adult survival over juvenile survival when only iteroparity is considered.
- When both developmental delay and iteroparity are modeled, both adaptations are favored under environmental uncertainty.
- Selective pressure on life-history delays increases with greater environmental variation.
Conclusions:
- Developmental delay and iteroparity are not mutually exclusive but can be co-favored adaptations in uncertain environments.
- Reproductive delay and adult survival can function as either adaptive strategies or constraints, requiring empirical validation.
- Natural-history studies are essential for parameter estimation to resolve the adaptive significance of these traits.
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